Electrical current

You will learn:

✔Current definition

✔Current Flow

✔ Series and Parallel Current

✔ Electricity Distribution

✔ Direct current (DC)

✓Alternating current (AC)

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Definition:

Electrical current, often referred to simply as current, is the flow of electric charge through a conductor. It is measured in amperes (A) and represents the rate of flow of electric charge past a given point in a circuit.. According to Ohms Law

For example, when you plug in an electronic device such as a lamp, the flow of electrons through the wires connecting the lamp to the power source constitutes an electrical current. The amount of current flowing through the circuit depends on factors such as the voltage of the power source and the resistance of the circuit components.

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Conventional Current Flow: This is the traditional model used in circuit analysis where current is assumed to flow from the positive terminal of a voltage source to the negative terminal. This model is based on the direction in which positive charges would hypothetically flow, although in reality, electrons are the carriers of electric current in most materials.

Non-conventional Current Flow:

This refers to the actual movement of electrons, which flow from the negative terminal of a voltage source to the positive terminal. This is the opposite direction of conventional current flow.

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Series Circuit:

In a series circuit, the components are connected end-to-end, forming a single path for the flow of current The same current flows through each component in the circuit.

• The total resistance in a series circuit is equal to the sum of the individual resistances of the components. 

• If one component fails (e.g., a bulb burns out in a series of Christmas lights), the entire circuit will be interrupted, and none of the components will work.

Parallel Circuit: In a parallel circuit, the components are connected across common points, forming multiple paths for the flow of current. The voltage across each component in the circuit is the same.

•The total resistance in a parallel

circuit is less than the resistance of any individual component because the total resistance is determined by the reciprocal of the sum of the reciprocals of each individual resistance.

• If one component fails in a parallel circuit, the other components will continue to operate normally because each campanent has its own separate path for current flow.

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Electricity distribution 

Electricity distribution refers to the process of delivering electrical power from

generating stations to consumers through a network of transmission and distribution. lines. This process involves stepping down the voltage levels for safe and efficient delivery to homes, businesses, and other

end-users

Generating Station: Electricity is generated at power plants, which can be hydroelectric, thermal, nuclear, or

renewable energy sources like wind or

solar.

Transmission: High voltage electricity (usually 110 kV or higher) is transmitted

over long distances via overhead power lines or underground cables to substations.

Substations: At substations, transformers.

step down the voltage to a lower level, typically around 11 kV or 33 kV, for further distribution.

Distribution Lines: Lower voltage

electricity is then distributed through a network of poles, wires, and underground cables to neighborhoods and industrial areas.

Consumers: Finally, electricity reaches homes, businesses, and other end-users where it powers appliances, lighting,

machinery, and other electrical devices.

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Direct current:

Direct current (DC) is an electrical current

that flows consistently in one direction through a conductor, without reversing its direction. Unlike alternating current (AC), which periodically changes direction, DC maintains a constant polarity. 

A common example, of direct current

is a battery-powered device, such as a flashlight. When you switch on the flashlight, the electrical current flows

from the battery's positive terminal to its

negative terminal, illuminating the bulb.

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Alternating current: 

Alternating current (AC) is an electrical current that periodically reverses. direction, changing its polarity over time. This type of current is commonly used in power distribution systems and most household electrical appliances.

Consider the electrical outlets: 

in your home. They provide alternating current

supplied by the power grid. When you plug

in a device, such as a laptop charger or

a vacuum cleaner, the alternating current

flows through the device, reversing.

direction many times per second (typically

50 or 60 times per second, depending on

the region's electrical frequency).

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Frequently asked question

Q: Why are copper wires used as connecting wires?

Answer:

Because they offer low resistivity for the

flow of electrons 

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Q: What happens to the resistance of

pure metals and semiconductors with an

Answer:

The resistance of pure metals increases

with the increase in temperature, and the resistance of semiconductors decreases

with an increase in Lemperature.

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Q: Define ampere?

Answer:

Ampere is defined as the unit of electric

current that is equal to the flow of one

Coulomb per second.